Square



C. L. BRONK.

(No Model.)

SQUARE.

Patented Aug. 26, 1890. fzyf.

we News Pneus co., wom-mnu, msumm UNITEDi STATES VPATENT OFFICE.

CHARLES L. BRONK, OF BROOKLYN, NEV YORK.

SQUARE.

SPECFICATION forming part of Letters Patent No. 435,086, dated August 26, 1890. Application filed April 17 l 1890. Serial No. 34910517. (No model.)

To a/ZZ whom it may concern.-

Be it known that I, CHARLES LEONARD BRONK, of Brooklyn, in the county of Kings, in the State of New York, have invented a new and useful Improvement on a Carpenters Steel Square; andI do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings, making a part of this specification.

My invention relates to an improvementin steel squares, in which the arms are pivotally secured together, so that one may be swung with relation to the other throughout an arc of ninety degrees.

The object is to so construct the joint between the two arms that the strain upon the pivotal point may be materially reduced and a bearing of such extent formed that there will be little or no liability of the arms wearing so as to be thrown out of a true perpendicular to each other when opened, and to further provide for a true lateral seat of the two arms and for automatically lockin g them in opened adjustment.

With these ends in viewmyinvention consists in certain features of construction and combinations of parts, as will be hereinafter described, and pointed out in claims.

A practical embodiment of .my invention is shown in the accompanying drawings, in which- Figure l is a View of the square in side elevation, the arms being broken and shortened in order to show the joint upon a larger scale. Fig. 2 is a view of the joint portion of the square in side elevation upon the 1'@- verse side from Fig. l, the arms in Figs. l and 2 being shown as in extended adjustment. Fig. 3 is a view of the joint and portions of the arms contiguous thereto in side elevation, showing the position of the joint when the arms are partially opened; and Fig. 4 is a transverse section through line o; of Fig. l.

A represents the wider and longer of the two arms, and B represents the narrower and shorter of the two arms, of a square of the general form in comlnon use. The two arms A and B are here shown graduated for a short distance from the joint only; but it is inL` tended that they shall be graduated throughn out their entire lengths, as is common.

The arm A is provided with a shallow recess a, extending for a considerable distance from its end, somewhat more than twice the Width of the arm B, and terminating at its lower end in a curve a', corresponding to a quarter of the circumference or more. This curved portion is provided with graduated divisionmarks to designate the different angles from one degree to ninety degrees and subdivisions thereof, as may be desired. Said recess a occupies two-thirds or more of the width of the arm A, thereby forming not only an elongated bearing in the direction of the length of the arm A, but also an extended bearing widthwise of the same.

The wall of the recess a is provided with an undercut a2, extending throughout both its curved and straight portions. The end of the arm A is further cut away along the edge of the recess a t'oward the arm B, forming an elongated notch, as shown at a3, the said notch terminating in a curved lower portion a4. The edge of the notch a3 throughout both its straight and curved portions is beveled to enter a corresponding under-cut, as will hereinafter appear.

The arm A is provided on its opposite face from that on which the recess a is located with an elongated shallow recess a5 for the reception of a dat bar-sprin g C. The portion a6 of said recess a5 near the end of the arm A extends through the arm A into the recess a, hercinbefore referred to, for the reception of the nose c of the said spring C, which nose c projects through th'e said portion a and forms a lock to secure the member or arm B i in its extended adjustment with relation to the arm A. I prefer to form the nose c of substantially rectangular shape, as shown, and bevel one of its corners, as shown at c', for the purpose of gradually forcing it back ward by the opening movement of the arm B. The spring C issecured with its back Hush with the surface of the arm A conveniently by means of a pair of short screws c2. It is intended that the recess a in the armAshall have a depth equal to about one-half the thickness of the arm A.

The arm B is provided on its end toward 2 43,5,csc

the arm A with a plate b, of substantially the shape and thickness of the recess a, hereinbefore referred to, and its edge b throughout both the straight and curved portions is beveled to correspond to the under-cut hereinbefor'e referred to in the wall of the recess a. The plate b is further provided with a lateral projectingportion b2, corresponding in shape and thickness to the notch or cut-away portion a3 in the arm A, and is provided along the straight and curved portions of its edge with an under-cut b3, `adapted to receive the beveled edge a4 of the notch a3. I find it convenient, as herein shown, to form the plate b and the projection b2 integral with the arm B.

The .plate b is provided near its upper end with Tan-'opening b4, adapted to receive with a close fit-the nose c of the spring O. -I further provide the beveled edge b of the plate b with an 'oblique shoulder b5 at the point where it iirst engages wit-h the nose c of the springC, for the purpose of gradually depressing the spring 'out of the way of the plate b as it slides intopositionwithin the recess a. without'the necessityof operating the'springv by the pressure of the hand. "lhe arm B is pivotally secured to ythe arm A by'nneans of a pivotal screw-or 'other suitable pivotal vconnectionfD, which extends through the plate Z) near its lower or 'curved edge and a considerable distance back from the front or inneredge of the arm A and the plate t.

Between the pivotal connection VD and the curved end of the plateb in the form of my invention shown there is provided a curved closed-end-slot- E through theend of the plate b. A set-screw d extends lthrough the curved Islot E into the Aarm A, preferably with its head Vflush with the face of the plate b. yIt will be observed that the two arms A and B when thus assembled have an extended bearing one upon the other and upon opposite sides of the arm A, tending to prevent any displacement of the relative position of the two arms when under strain. It will also be observed that the point where the nose of the spring locks the two arms together is'at such a distance from the pivotal point of "he two arms that the said armsare effectuallyfocked against any liability of displacement xhen under strain in a direction to close them.

. What I claim as my invention isl. The combination, with the arms of a square, the one provided with a'n elongated shallow recess and the other with an elongated thin plate corresponding to said recess, of a pivotal connection between the twol arms at a considerable distance from the angle formed by the inner -edges of the two arms, and a locking device near the opposite end of said corresponding recess and plate from the pivotal connection, substantially as set Jforth.

2. The herei-n-described square, oneof the arms-being provided with. an elongated Wide shallow recess a, having a curved end, and the other with' a plate corresponding in shape and thickness to said recess, a pivotal vconnection between the two arms at a point near the said curved ends, one of the arms being provided with a curved slot and the other with a set-screw extending within the curved slot, a spring seated in the arm provided with a shallow recess and having its nose` projected Within the recess to engage an opening in the opposite arm, the two arms being further provided the one with an elongated notch and the other with an elongated lateral projection to correspond with the notch and located upon the opposite side' ofthe square from the recess and plate hereinbefore referred to, substantially as set forth.

CHARLES L. BRONK.

WVitnesses:

HERBERT C. SMITH, JAM-Es H. AYREs. 

